1. Field of the Invention
This invention relates to a group supervisory control system for an elevator system.
2. Description of the Prior Art
In the typical group supervisory control system for an elevator system, when a hall call is registered, an elevator car suitable for responding to the hall call is selected depending upon data required for the group supervisory control, whereby the hall call is allocated to use car. This is the typical system which is described, for example, in U.S. Pat. No. 4,244,450. A registration of a hall call, a time for continuing a registration of a hall call, a registration of a car call, car load, car position and car direction are used as the data for the group supervisory control. These data are data at the present or past time. Even though the data are suitable at the present time, it is not always suitable in the future.
Referring to FIG. 1, one example will be illustrated.
In FIG. 1, the references (1)-(10) respectively designate 1st-10th floors; (a)-(c) respectively designate cars No. 1-No. 3; (1a) designates up calls registered at a hall of the first floor (1); (3b), (5b), (7b)-(10b) respectively designate down calls registered at halls of 3rd (3), 5th (5), 7th (7)-10th (10) floors; (4c), (6c), (8c), (10C) respectively designate car calls for 4th, 6th, 8th and 10th floors. The car (a) is in up travel responding to the car calls (4c), (6c), (8c), (10c). The car (b) is in down travel at the 6th floor (6) under allocation of the down call (3b) at the 3rd floor. The car (c) is in down travel at the 7th floor (7) under allocation of the down call at the 5th floor. (The down calls (7b)-(10b) have not been given.) In a time zone for greater probability of down calls, there is great probability of the down call (7b)-(10b) just after the allocations for the cars (b), (c). Such allocation is given under the present condition of the car position and the calls. Even though the down calls (7b)-(10b) are given just after the moment, there is no car to respond to the down calls and persons who register down calls (7b)-(10b) at the 7th-10th floors have to wait for a long time. When the cars (b), (c) respectively stop at the 3rd and 5th floors (3), (5) in response to the down calls (3b), (5b), the car call at a lower floor (especially the first floor (1)) by the passengers entered at these floors. The cars (b), (c) should be in downward travel in response of the car call and accordingly, the responses to the down calls (7b)-(10b) at the upper floors are delayed.
When many passengers are entered at the first floor (1), many car calls of the cars (b), (c) are registered at the first floor (1). The cars (b), (c) stop often and there is no response to the down calls (7b)-(10b) by any car for a long time. There is a further problem of passing these floors because of the full passenger load in the cars.